Summary Of Significant Accounting Policies (Summary Of Currency Exchange Rates) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Australian Dollar [Member] | Spot Rate [Member]
Currency Exchange Rates [Line Items]
Foreign currency exchange rate	0.7230	0.7286	0.8173
Australian Dollar [Member] | Average Rate [Member]
Currency Exchange Rates [Line Items]
Foreign currency exchange rate	0.7440	0.7524	0.9027
New Zealand Dollar [Member] | Spot Rate [Member]
Currency Exchange Rates [Line Items]
Foreign currency exchange rate	0.6958	0.6842	0.7796
New Zealand Dollar [Member] | Average Rate [Member]
Currency Exchange Rates [Line Items]
Foreign currency exchange rate	0.6973	0.7004	0.8306